440 Cast Crank Balancing

[m79ded]

Hi

I'm putting together a 75 440 engine and I got Probe pistons on Ebay which are 687 gr & 150 gr pins. I also got from CNC motorsports Scat h-beam rods 6.760. However I do have a perfect original cast crank which I would like to use.

Do I have to balance that externaly? or because of the lighter components do you think I can internally balance it. Anybody done something like this?

Any help would be appreciated.

Thanks

 

[patrick66]

The cast crank can be balanced with Mallory metal, but that is VERY pricey. Do you still have the original balancer? If not, I have a choice of three that I'd sell.

 

[m79ded]

The cast crank can be balanced with Mallory metal, but that is VERY pricey. Do you still have the original balancer? If not, I have a choice of three that I'd sell.

Thnx Patrick66 But I do have a cast crank dampner. I was trying to avoid using it because I have a new BHJ SFI Dampner I would like to use and can also avoid buying a B&M cast crank Flexplate

 

[Meep-Meep]

If you reduce the reciprocating mass substantially you can probably get away with trimming the counterweights and no heavy metal. Good post by the way. And by all means reply with your bob weight results.

 

[m79ded]

If you reduce the reciprocating mass substantially you can probably get away with trimming the counterweights and no heavy metal. Good post by the way. And by all means reply with your bob weight results.

Definitely I will, It would help another fellow member out in the event that someone else does a similar build. After all if it can be done economically using a cast crank and avoid the balancing weights on the torque as well as special flexplate and dampner it would be a plus.

Like myself if it's a mild street build making under 500 why not go that way and not really have to hunt down an expensive harder to find steel crank.
Our members would benefit.

Thanks for the suggestion Meep

 

[JedIEG]

I did this with my dad's 360. I balanced the engine with it put together with a few calculations and then shaving the counterweight on the damper and filling in the flywheel with slugs. In the end the counter weight on the balancer was almost gone and the holes in the flywheel almost filled. You could easily take a few more grams off the pistons while the engine is apart and get a good streetable balance

 

[lewtot184]

850gr piston and pin is quit a bit lighter than stock. i bet using the cast dampner with an externally balance aftermarket flex plate will internally balance.